Introduction to Evolution and Genetics

Question 1

What creates variation in a population

Answer 1

mutation, recombination and gene flow

Question 2

What processes influence variation in a population

Answer 2

selection and genetic drift

Question 3

Who was the first to advocate for evolution

Answer 3

Jean-Baptiste de Lamarck

Question 4

What was Lamarck’s theory of evolution

Answer 4

Lowly forms of life arise spontaneously from inanimate matter
They progress towards greater complexity
Environment alters the needs of the organisms
Use and disuse alter morphology
This is transmitted to the next generation

Question 5

What were Darwin’s main ideas

Answer 5

All organisms have descended with modification from a common ancestor
the chief agents of modification is natural selection on individual variation

Question 6

What did Darwin study to develop his theory

Answer 6

Fossil record
Geographic distribution of species
Comparative anatomy
Embryology
Studies on domestic animals

Question 7

What were the initial problems with Natural Selection?

Answer 7

Peeps were ready to accept biological evolution, but thought the struggle for existence was at the species level, not the individual

Question 8

Popular misconceptions about evolution

Answer 8

There is no “higher goal”
No progress from “lower” to “higher” life forms
Natural selection acts at individual level
Evolution and natural selection are amoral
The “law” of natural selection cannot be used to justify the class struggle, capitalism, etc

Question 9

What was the blending problem for natural selection

Answer 9

How can traits values segregate and not merge to a mean value with no variation?
Mixing paints on a paint pallet

Question 10

Who solved the blending problem but introduced another

Answer 10

Gregor Mendel in 1900

Heritable traits were thought to be discontinuous

Question 11

What is the modern synthesis of evolution

Answer 11

Populations contain genetic variation that arises spontaneous and at random
This variation is subject to random fluctuations
Natural selection favours certain variants that increase fitness
Genetic variation can be exchanged between populations (gene flow) and occasionally between species
Recombination shuffles variation and generates new genotypes
Over time, genetic changes accumulate so that populations become reproductively isolated

Question 12

How does biodiversity and genetic complexity increase?

Answer 12

Duplication and divergence
Symbiosis
Epigenesis

Question 13

How does duplication and divergence increase biodiversity and genetic complexity

Answer 13

Duplication does not increase genetic information but it does give substrate for selection and drift leading to divergence

Question 14

How does symbiosis increase biodiversity and genetic complexity

Answer 14

Origin of eukaryotic life, but also evolution of chromosomes (linking genes), associations between plants and fungi, animals and algae

Question 15

How does epigenesis increase biodiversity and genetic complexity

Answer 15

Heritable changes in gene expression or cellular phenotype not due to changes in the DNA

Question 16

What is Kumura Neutral Theory

Answer 16

Most intraspecific variability at the molecular level is neutral and variation in maintained by the input of new mutations balanced by the loss due to drift
Few DNA polymorphisms in a species are due to positive or balancing selection

Question 17

What is the process of epigenetic regulation

Answer 17

Not all adaptive evolution occurs through mutations and changes in the DNA code
Heritable changes occur in gene expression
Modifications are DNA methylation and histone modification
Changes may remain through cell divisions and across generations (i.e. heritable)
Lamarck!`

Question 18

How much needs to die to be class as a mass extinction

Answer 18

75% taxa

Question 19

What is the current extinction rate?

Answer 19

Estimated 1000-fold increase over ‘background extinction rate (not yet 75%)

Question 20

What has been affected by the sixth extinction

Answer 20

extinction of megafauna in the late Pleistocene, but currently most taxa

Question 21

What is the cause of the sixth extinction

Answer 21

human population size expansion, loss and fragmentation of habitat, pollution, over exploitation, climate change

Question 22

How do we slow the extinction rate on a global scale

Answer 22

Reducing pollution and greenhouse gas emission and protection of the ozone layer

Question 23

How do we slow the extinction rate on a local scale

Answer 23

Protecting habitat, life-style changes (food, recycling etc.)

Question 24

How do we slow the extinction rate on a species level

Answer 24

Protecting species in situ
Ex situ conservation in zoos
Reintroduce animals (plants) when habitat is restored and safe

Question 25

What are the risks of captive breeding

Answer 25

Inbreeding depression
Loss of genetic variation
Outbreeding depression (hybridisation)
Adaptation to captive environment
Accumulation of new deleterious mutations

Question 26

How to minimise the risks of captive breed

Answer 26

breeding with wild individuals
be aware of local adaptations
maximise migration regime?
purging regime = removing deleterious mutations through inbreeding

Question 27

What is the main concern over captive population size

Answer 27

Too large, you get too much adaptation to captivity, too small and there is too much inbreeding depression

Question 28

When doing breeding experiments, why would you limit the amount of offspring, from each individual

Answer 28

By equalising the reproductive ability of everyone you reduce the effects of selection

Question 29

Why does deleterious alleles arise in captivity

Answer 29

inbreeding and all ill animals get medicine

Question 30

What were the main conclusions of Oosterhout et al 2007

Answer 30

During reintroduction
Many fish died from parasites (epidemics)
Inbreeding Regime - lowest survival
Outbred guppies from the largest natural population - had the highest survival

Question 31

Why did parasites cause such high mortality in guppies

Answer 31

Medication was used in captivity

Individuals were not pre-exposed to parasites before release

Question 32

what animals are extinct in the wild?

Answer 32

Th Gaum rail and the Californian condor

Question 33

Story of the Guam rail

Answer 33

Guam rail, a small, flightless bird, was nearly driven to extinction by the invasive brown tree snake, which was accidentally brought to the island by the U.S. military. The rails now live only in captive environments, including the National Aviary in Pittsburgh.

Question 34

Story of the californian condor

Answer 34

In 1987, the 27 California condors left in the world were taken into captivity, making them extinct in the wild. in California zoo

Question 35

retention of genetic variation in captive breeding programs can be maximized by:

Answer 35

maximizing the initial genetic variation by using adequate numbers of founders
minimizing the number of generations in captivity by seed storage in plants, cryopreservation or breeding from older animals
maximizing population size
maximizing N e / N .

Question 36

Define ex situ conservation

Answer 36

“off-site conservation”, protecting organisms outside there natural habitat, often in zoos or botanical gardens

Question 37

What are the IUCN goals for conservation programmes

Answer 37

establishing populations in secure ex situ locations educating and engaging the public on conservation issues
providing a focus for fund-raising efforts for conservation
providing animals for research on the basic biology of species, knowledge that can then be applied to conservation of species in the wild
providing animals for reintroduction programs, where applicable.

Question 38

what are the 6 stages of captive breeding and reintroduction

Answer 38

Recognizing decline of the wild population and its genetic consequences
Founding one or more captive populations
Expanding the captive populations to a secure size Managing the captive population over generations Choosing individuals for reintroduction
Managing the reintroduced population (probably fragmented) in the wild.